iDisk For windows

I need a program used to back up files to a web server (exactly like iDisk for mac users). The user should get 10mb of data (unregistered), and using a web script (that will also need to be included) be able to register and buy a product code. 10$ a month for 10GIGS, 20$ a month for 25GIGS, and 100$ a month for unlimited space. I need client side and server side scripting. Both should have GUI and be easy to use.

monthly prices should be able to be changed....and payment should be set up with PAYPAL.